Cap and plug for masking or shipping

ABSTRACT

A method for providing a cured coating on a tube, comprising masking and sealing an end of the tube with a self-venting cap and plug, the cap and plug comprising a tubular member comprising a resilient material having an open end and a closed end, and having an outermost sidewall; the outermost sidewall having an interior surface having an annular ridge; the closed end having a hollow dome portion defined by an annular recess, the annular recess defining an inner sidewall with an upwardly-extending annular recess, the inner sidewall containing at least one gas venting groove terminating along the longitudinal extent of the inner sidewall, and the inner sidewall being spaced from the interior surface of the outermost sidewall of the tubular member a distance greater than the height of the inwardly-directed ridge; coating the tube with a curable coating; and curing the curable coating at an elevated temperature.

This application is a divisional of application Ser. No. 11/585,131,filed Oct. 24, 2006.

BACKGROUND OF THE PRESENT INVENTION

The present invention is directed to a self-venting cap and plug whichis particularly adapted for protective use in masking or shipping.

A variety of closure means are known which are used for a variety of enduses such as to seal an end of a pipe, providing masking means,providing means to protect the end of a pipe or tube during shipping,etc.

Exemplary patents which disclose a variety of end closures include butare not limited to U.S. Pat. Nos. 2,095,528; 2,321,667; 2,727,651;3,307,552; 3,490,488; 3,661,184; 3,744,528; 3,927,798; 3,987,930;4,139,005; 4,204,606; 4,210,179; 4,335,756; 4,483,371; 4,889,256;5,613,615; 5,706,860; 6,367,508; 6,408,887; 6,562,300.

However, despite the various advantages that may result from the use ofthe various end caps or closures disclosed by the above patents, a needstill exists to provide a cap and plug closure that provides enhancedclosure with respect to the tube or pipe with which the cap and plug isused, together with desirable venting for gases present in the tube orpipe.

OBJECTS AND SUMMARY OF THE PRESENT INVENTION

It is accordingly an object of the present invention to provide a capand plug which provides improved venting of gases from within a cappedtube or pipe.

It is further an object of the present invention to provide a cap andplug which provides improved masking of a tube or pipe.

In accordance with the present invention, there is thus provided amethod for providing a cured coating on a pipe or tube, said methodcomprising:

masking and sealing an end of a pipe or tube to be coated with aself-venting cap and plug, said cap and plug comprising a tubular membercomprised of a resilient material having an open end and a closed end,and having an outermost sidewall extending therebetween;

said outermost sidewall having an interior surface having aninwardly-directed ridge which extends from said interior surface as wellas circumferentially along at least a centrally-disposed portion of saidinterior surface of said outermost sidewall and spaced from said closedend;

said closed end comprising a centrally-positioned upwardly-extendinghollow dome portion defined by a downwardly-extending open-ended annularrecess in a top surface of said closed end, said annular recess alsodefining an inner sidewall spaced from and opposing said interiorsurface of said outermost sidewall of the tubular member with anupwardly-extending annular recess being formed therebetween,

said inner sidewall containing at least one gas venting groove extendingalong the longitudinal extent of said inner sidewall from an upperportion of said inner sidewall to a lower portion of said innersidewall, said at least one gas vent groove terminating along alongitudinal extent of said inner sidewall, and

the inner sidewall being spaced from said interior surface of theoutermost sidewall of the tubular member a distance greater than theheight of the inwardly-directed ridge.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a view in perspective of the top portion of the cap and plugof the present invention.

FIG. 2 is a view in perspective of the bottom portion of the cap andplug of the present invention.

FIG. 3 is a bottom view of the cap and plug of the present invention.

FIG. 4 is a view in cross-section of the cap and plug of the presentinvention.

FIG. 5 is a view in cross-section of another embodiment of the cap andplug of the present invention.

DETAILED DESCRIPTION OF THE PRESENT INVENTION

The improved cap and plug of the present invention will be described inconnection with the Figures.

The cap and plug 1 shown in the Figures is a molded tubular membercomprised of a resilient material and having a closed end 3 and an openend 5, and having an outermost sidewall 23 therebetween.

The sidewall 23 has an interior surface 9 which has an inwardly-directedridge 7 extending circumferentially along at least a centrally-disposedportion of the interior surface of the sidewall. The inwardly-directedridge 7 is shown in FIG. 4 as extending along a centrally-disposedportion of the interior surface. FIG. 5 depicts an embodiment whereinthe inwardly-directed ridge 7 extends to the open end of the body.

The closed end comprises a centrally-positioned hollow dome portion 11in a top surface thereof. The dome portion is defined by adownwardly-extending open-ended annular recess 21 in the top surface.The annular recess 21 also define an inner sidewall 15 spaced from andopposing the interior surface 9 of the outermost sidewall of the tubularmember.

The inner sidewall 15 defined by the annular recess 21 contains at leastone gas vent groove 17 extending along the longitudinal extent of theinner sidewall from an upper portion of the inner sidewall toward alowermost portion of the inner sidewall, and terminating along thelongitudinal extent of the inner sidewall. While two vent grooves aredepicted in FIG. 3 positioned at opposite sides, the use of more thantwo vent grooves may be appropriate as desired.

The inner sidewall 15 being spaced from the interior surface 9 of theoutermost sidewall defines an upwardly-extending annular recess 13 andis spaced from the interior surface 9 of the sidewall of the tubularmember a distance greater than the height of the inwardly-directedridge. Preferably, the uppermost extent of the inwardly-directed ridgeis spaced longitudinally from the lowermost extent of theupwardly-extending annular recess 13. Such spacing enhances the abilityof the cap and plug to snugly engage with an inserted pipe or tube.

The particular configuration of the end surface of the annular recess 13is not critical to practice of the present invention. For instance, FIG.4 depicts the end of the annular recess 13 as including a curvedportion, while FIG. 5 depicts the end of the annular recess 13 asincluding an oblique surface.

During use, the cap and plug of the present invention is employed withadvantage during the coating of tubes or pipes, whereby an end portionof the tube or pipe is required to be masked during the coating process.Such pipes or tubes are generally hollow and open-ended at one end. Forinstance, during powder coating of a metal tube or pipe, the cap andplug of the present invention, when inserted onto the end of the tube orpipe, serves to mask the covered portion of the tube or pipe during thecoating process. The design of the cap and plug also provides additionaladvantages. Prior to being coated, it is frequently necessary to washthe exterior surface of the tube or pipe to prepare the surface forcoating. It is desirable to seal the end of the tube or pipe during thewashing process to prevent entry of wash liquid or contaminants fromentering the interior of the hollow tube or pipe. The presence of thecap and plug of the present invention accordingly serves to seal the endof the tube or pipe.

Further, after the coating step, it is generally necessary to cure thecoating on the surface of the tube or pipe which involves subjecting thecoated tube or pipe to elevated temperatures sufficient to cure thecoating. The exposure of the capped tube or pipe to elevatedtemperatures causes gas (such as air) trapped in the capped tube or pipeto expand. Absent some means to permit such expanded gas to escape, thecap and plug may be blown off the end of the tube or pipe.

The present invention addresses this issue by providing a cap and plugcomprised of a material which becomes sufficiently flexible at theelevated curing temperature such that, as the internally-trapped gasbegins to expand, the walls of the cap and plug are caused to expand toan extent sufficient to permit the expanding gas to escape without thecap and plug being blown off the pipe or tube. The presence of the gasvent grooves 17 also serves to assist the internally-trapped gas toescape toward the top portion of the cap and plug. The presence of thedome portion permits heated gas to also expand therein which flexes theadjacent inner surfaces away from the end of the pipe or tube to assistin venting gas.

The plug body can be formed from any conventional polymeric materialwhich provides the requisite balance of physical stability andflexibility during use. Any conventional moldable polymer such asflexible polymeric materials can be used as the raw material for theplug body of the present invention. Thermoplastic rubber or elastomericmaterials are preferred to permit adequate flexibility when beinginserted into a cavity for sealing, while maintaining desired resiliencefor purposes of sealing. The material chosen shall be both dimensionallystable at ambient and those elevated temperatures used for curing anycoating applied to the pipe or tube. Such materials are well known inthe art and one of ordinary skill in the art can readily select anappropriate material for use in the present invention.

The plug may be made by any conventional molding process, with themethod of manufacture being well within the skill of the practitioner inthe art. For instance, the cap and plug may be formed by injectionmolding processes known to those skilled in the art. In such a process,a polymeric material such as polyethylene or polypropylene material maybe used that yields a cap body sufficiently elastic or conformable topermit the body to snugly engage the end of a pipe or tube whileretaining sufficient stability and exhibiting the desired flexibility atcuring temperatures. Accidental disengagement of the cap body is thusavoided.

1. A method for providing a cured coating on a pipe or tube, said methodcomprising masking and sealing an end of said pipe or tube to be coatedwith a self-venting cap and plug, said cap and plug comprising a tubularmember comprised of a resilient material having an open end and a closedend, and having an outermost sidewall extending therebetween; saidoutermost sidewall having an interior surface having aninwardly-directed ridge extending from said interior surface as well ascontinuously around the entire inner circumference of the tubular memberalong at least a centrally-disposed portion of said interior surface ofsaid outermost sidewall and spaced from said closed end; said closed endcomprising a centrally-positioned upwardly-extending hollow dome portiondefined by a downwardly-extending open-ended annular recess in a topmostsurface of said closed end, said annular recess also defining an innersidewall spaced from and opposing said interior surface of saidoutermost sidewall of the tubular member with an upwardly-extendingannular recess being formed therebetween, said inner sidewall containingat least one gas venting groove extending along the longtitudinal extentof said inner sidewall from an upper portion of said inner sidewall to alower portion of said inner sidewall, said gas venting grooveterminating along the longitudinal extent said inner sidewall, and saidinner sidewall being spaced from said interior surface of said outermostsidewall of said tubular member a distance greater than the height ofsaid inwardly-directed ridge; coating said pipe or tube with aheat-curable coating, and curing said heat-curable coating at anelevated temperature.
 2. The method of claim 1, wherein an uppermostextent of said inwardly-directed ridge is spaced longitudinally from alowermost extent of said upwardly-extending annular recess.
 3. Themethod of claim 1, wherein said upwardly-extending annular recessincludes an oblique surface at an uppermost portion thereof extendingacross said recess.
 4. The method of claim 1, wherein saidinwardly-directed ridge extends to said open end.
 5. The method of claim1, wherein said inner sidewall includes multiple gas venting grooves.